Protection Algorithm Research Articles

A Robust Integrated Watermarking Algorithm for Vector Geographic Data Copyright Protection

Vector geographic data play an important role in the natural resources and environment sector as well as in other location information services. This is also one of the types of data where the cost to create it is relatively large because of the difficulty in surveying, collecting, and authorizing. The rapid development of the Internet has created many advantages in the distribution, exploitation, and use of vector geographic data, but it also gives rise to many problems such as duplication, redistribution, forgery, and illegal data use. The theft on the Internet is becoming more and more sophisticated and the number of violations is increasing, showing the urgent need to research and develop an effective solution to protect the copyright of vector geographic data and prevent them from being illegally collected and used. Among the major studies and solutions, digital watermarking emerges as an effective method and is an active research area for copyright protection. Towards a good solution for copyright protection of vector geographic data, our study proposes a new algorithm with three main contributions, including: (1) generating short, pseudo-random meaningful watermarks to in-crease robustness and to enable automated as well as visual manual verifying; (2) building a uniformly distributed mapping between the vertex coordinates and the watermark bit indexes to increase the robustness of the watermarks; and (3) integrating two types of watermarks, namely, spatial domain-based watermarking and zero-watermarking to be resistant to most common attacks on geographic vector data. The algorithm works on all types of vector geographic data, including points, polylines, and polygons.

Privacy preserved data sharing using blockchain and support vector machine for industrial IOT applications

The Industrial Internet of Things (IIoT) paradigm's fast expansion in the amount of information created from linked devices creates new opportunities for improving the service quality and applications through sharing of data. Data security is a significant problem since training and Support Vector Machine (SVM) classifier often involves compiling tagged IoT data from several organizations. Beyond causing the suppliers to lose money, disclosing sensitive information might cause significant problems. To solve these issues, introduced a secure SVM, which is a Privacy-Preserving SVM (PP-SVM) training method using block chain-based encoded IoT data, to fill the void between ideal assumptions and practical restrictions. IoT messages are encrypted before being stored on a decentralized system because Block chain offers safe and dependable data exchange platforms across several data sources. Using a homomorphic cryptographic algorithm, Paillier, reliable modules have been developed, such as protected algebraic multiplying and protected comparison. Furthermore, a protected SVM learning algorithm that only needs two conversations during a single step has been created. According to stringent security assessment, proposed approach guarantees SVM model parameters for data professionals and secrecy of sensitive information for each data source. Extensive testing backs up effectiveness of the suggested plan.

An enhanced sensitive power differential protection for series compensated transmission lines in renewable generation intensive power systems

Series compensation is widely used to improve the electrical characteristics of long transmission lines and increase the power transfer capability. However, the insertion of a series capacitor introduces various phenomena that affect the performance of traditional distance relays. Moreover, the fault characteristics of renewable generation systems coupled with generation outputs that vary with weather patterns produce additional complications to the protection of transmission lines. This paper proposes the application of an enhanced sensitive power differential protection (SPDP) algorithm to the protection of series compensated transmission lines. The algorithm incorporates a criterion that improves the security of the protection by inhibiting the SPDP algorithm from operating for faults external to the protected line. Performance of the enhanced SPDP algorithm has been evaluated on a test system built in Digsilent Powerfactory software. Various in-zone and out-of-zone fault cases were simulated at different compensation levels and fault resistances. The results showed that the enhanced SPDP protection technique can detect in-zone faults along practically the entire transmission line (99.99 %) for compensation levels up to 90 %. The method operated reliably for faults with resistances up to 330 Ω.

Retracted: Privacy Protection Algorithm Model of We-Media Network from the Perspective of Big Data

Retracted: Privacy Protection Algorithm Model of We-Media Network from the Perspective of Big Data

National-Level Multimodal Origin–Destination Estimation Based on Passively Collected Location Data and Machine Learning Methods

Along with the development of information and positioning technologies, there emerges passively collected location data that contain location observations with time information from various types of mobile devices. Passive location data are known for their large sample size and continuous behavior observations. However, they also require careful and comprehensive data processing and modeling algorithms for privacy protection and practical applications. In the meantime, the travel demand estimation of origin–destination (OD) tables is fundamental in transportation planning and analysis. There is a lack of national OD estimation that provides time-dependent travel behaviors for all travel modes. Passively collected location data appeal to researchers for their potential of serving as the data source for estimation and monitoring of large-scale multimodal travel demand. This research proposes a comprehensive set of methods for passive location data processing including data cleaning, activity location and purpose identification, trip-level information identification, social demographic imputation, sample weighting and expansion, and demand validation. For each task, the paper evaluates the state-of-the-practice and state-of-the-art algorithms and develops an applicable method jointly considering different features of various passive location data sources, imputation accuracy, and computation efficiency. The paper further examines the viability of the method kit in a national-level case study and successfully derives the multimodal national-level OD estimates with additional data products, such as trip rate and vehicle miles traveled, at different geographic levels and temporal resolutions.

An ultra-fast directional protection scheme for DC microgrids based on high-order synchrosqueezing transform

Protection of Direct Current (DC) microgrids is a challenging task because of large currents within a few milliseconds after the occurrence of a DC fault, which causes serious damage to converters. The present study introduces a protection algorithm based on Traveling Waves (TWs) to detect and locate faults. The proposed method implements the High-order Synchrosqueezing Transform (HOSST) to capture TWs using local measurements. Unlike conventional methods, HOSST can analyze signals in both time and frequency domains by creating a concentrated energy in the time–frequency representation. By extracting impulse features, HOSST detects TWs with high accuracy even in a noisy environment for different types of DC faults with various fault resistances. The proposed method can identify external and internal faults by determining the polarity of TWs, which makes the relays operate properly within their protection zone and prevents mal-operation. To demonstrate the efficiency of the proposed method, it is applied to a DC microgrid. The results show the high accuracy of the presented approach in the fault location with a slight error with selectivity, reliability, sensitivity, and high speed, which is independent of the voltage level and configuration. In addition, the certainty of the proposed method is higher than the previous studies due to the simultaneous use of current and voltage.

A Fast and Robust Local-Based Protection Algorithm Based on the High-Frequency Transient for HVDC Grid

With the expansion of HVDC grids, short-circuit faults and their protection issues are among the main challenges of these networks, which should be given more attention. This study presents an investigation of the DC side fault current in HVDC grids during the transient period. Also, a fast and robust protection algorithm is introduced that is essential for secure and appropriate HVDC grids operation. The Short-Time Fourier Transform (STFT) is applied to extract the frequency components of the fault current, and the time features of these components are utilized as the basis of the proposed algorithm. A four-terminal cable-based HVDC grid with bipolar configuration is modeled via EMTP, and a wide range of simulation scenarios are applied for various fault locations, fault impedances, and operation points. Furthermore, the algorithm thresholds are determined with the explicit procedure. Simulation results indicate that the proposed method is fast, selective, sensitive, and robust against AC-side fault, operating condition variations, fault distance, and fault direction. Also, it has an appropriate performance during high impedance faults.

Innovative Loss of Field Protection Algorithm for Small-Scale Synchronous Generators

Although conventional loss of field (LOF) protection schemes, especially impedance-based ones, are widely used for large-scale synchronous generators, they may not provide proper performance for small-scale synchronous generators (SSSGs) due to various concerns including, (i) large tripping time for unrecoverable LOF (ULOF) which may lead to severe voltage drop and stalling of nearby induction motors, (ii) LOF function maloperation during islanding events, and (iii) LOF function maloperation during recoverable LOF events. To resolve these issues, a new adaptive LOF protection logic is proposed for SSSGs. After ULOF events, the automatic voltage regulator (AVR) output gradually increases, while the SSSG internal voltage does not considerably increase. Based on this principle, some measurable or easily calculable parameters, including AVR output and SSSG internal voltage, are adopted to discriminate ULOF from other disturbances. Meanwhile, the proposed logic is wisely equipped with an adaptive time delay to prevent stalling of nearby induction motors and enhance operation speed during ULOF. Performance of the proposed algorithm is evaluated under various LOF and islanding events as well as short circuits. Obtained promising results confirm desirable performance of the proposed approach. Besides, compared to the impedance-based method, the proposed adaptive time delay considerably improves the security and reliability.

ANALYSIS OF DIFFERENTIAL RELAY PROTECTION ALGORITHMS AND THEIR MODELLING IN MATLAB

The paper is devoted to identifying the prospects for software implementation of differential relay protection. The purpose of this study was to analyse the algorithms of the devices' operation, which allowed to create a mathematical model in the MATLAB software environment with the prospect of integration in the form of a single regional relay protection server into the unified energy system of Ukraine. It has been established that virtual models have both advantages and disadvantages compared to digital-analog devices. Their positive feature is that, due to the block principle of construction, it is possible to easily change not only the parameters but also the configuration of the primary network. The disadvantage is that the configuration of virtual protections differs from the configuration of their prototypes - real relays and terminals. The article evaluates the existing, widely used methodology and considers the actual algorithms of two-stage differential relay protection. It is established that differential protection has two stages: 1 - fast-acting differential current cut-off; 2 - sensitive differential current protection with inhibition from through current and recovery from magnetisation current surges. A simplified diagram of a fragment of the electrical system and differential relay protection of a transformer are developed and presented in MATLAB. The algorithms are considered in detail, and it is established that with their help and with the help of the considered principles of differential protection in the Simulink package, the logic of the model is implemented similarly to the logic of microprocessor-based transformer protection "RS-83DT2" of RZA Systems LLC, SPAD 346 C of ABB. Based on the modelling results, the oscillograms of primary currents of normal mode and emergency modes with external and internal short circuits are obtained. The conclusions establish the prospects of using this model and algorithms for the development of a software solution for the relay protection server and for future integration into the integrated power system.

Two-terminal traveling-wave-based non-homogeneous transmission-line protection

This paper presents a two-terminal traveling-wave-based protection algorithm applied to non-homogeneous transmission lines comprising any number of sections with different topologies and considering the effect of the sampling rate. Existing two-terminal traveling wave protection functions cannot protect the line under close-in faults and present limitations in non-homogeneous transmission lines. However, the effects of the sampling rate, considered in the proposed method, result in well-defined protection and unprotected zones, essential for protection security and coordination to deal with the issue of close-in faults in non-homogeneous transmission lines. Furthermore, the algorithm can accurately detect the faulted section, allowing its use in advanced protection functions such as adaptive automatic auto-reclosing and high-speed protection schemes. A protection device was modeled considering a sampling frequency equal to 1 MHz, including functions to detect traveling waves via wavelet transform, and the proposed protection algorithm to discriminate line internal from external faults, and to select the faulted section. The algorithm was evaluated using a large number of ATP fault simulations. The results show that the algorithm is robust and reliable for protection devices installed in non-homogeneous lines.

An algorithm for distance protection based on the change of the voltage phase angle

Conventional distance protection methods usually require additional filtering of the input signals to remove the influence of the DC component and the distortion of sinusoidal signals. The paper shows an algorithm that does not require additional filtering of the input signals. The proposed algorithm uses measured voltages at the beginning of the line and auxiliary voltages as input signals. The auxiliary voltages were calculated from measured currents and voltages at the beginning of the line and known line parameters. The algorithm compares the instantaneous values of the measured and calculated auxiliary voltages and detects a fault on the line based on the change in the phase angle of the voltage. Testing of the presented algorithm was performed with signals obtained from computer simulations of line faults and recordings of faults from protection devices from the real network. The obtained results confirmed that the algorithm represents fast and sensitive protection of transmission lines.

Risk of occurrence of electromagnetic interference from the application of transcutaneous electrical nerve stimulation on the sensing function of implantable defibrillators.

Transcutaneous electrical nerve stimulation (TENS) is an established method for pain relief. But electrical TENS currents are also a source of electromagnetic interference (EMI). Thus, TENS is considered to be contraindicated in implantable cardioverter-defibrillator (ICD) patients. However, data might be outdated due to considerable advances in ICD and cardiac resynchronization therapy (CRT) filtering and noise protection algorithm technologies. The aim of this pilot safety study was to re-evaluate the safety of TENS in patients with modern ICDs. One hundred and seven patients equipped with 55 different models of ICD/CRT with defibrillators from 4 manufacturers underwent a standardized test protocol including TENS at the cervical spine and the thorax, at 2 stimulation modes-high-frequency TENS (80 Hz) and burst-mode TENS (2 Hz). Potential interference monitoring included continuous documentation of ECG Lead II, intracardiac electrograms and the marker channel. Electromagnetic interference was detected in 17 of 107 patients (15.9%). Most frequent were: interpretations as a premature ventricular beats (VS/S) in 15 patients (14%), noise reversion in 5 (4.6%) which resulted in temporary asynchronous pacing in 3 (2.8%), interpretation as ventricular tachycardia/ventricular fibrillation in 2 (1.9%), and premature atrial beat in 2 (1.9%) patients. Electromagnetic interference occurrence was influenced by position (chest, P < 0.01), higher current intensity (P < 0.01), and manufacturer (P = 0.012). Overall, only intermittent and minor EMI were detected. Prior to the use of TENS in patients with ICDs, they should undergo testing under the supervision of a cardiac device specialist.

Multi-Layer Smart Fault Protection for Secure Smart Grids

The trend toward Smart grid (SG) is increasing significantly by incorporating Distributed Generators (DGs), which leads to new challenges, especially in protection systems. SGs should strengthen robust environments against cybersecurity threats. So, the cybersecurity of future SGs is essential. This paper proposes a multi-layer protection scheme for the Medium Voltage (MV) Distribution System (DS), especially with reconfigurable SGs. The main protection algorithm is based on Artificial Intelligence (AI), utilizing the communication between all protective devices (PDs) in the grid, whereas as backup protection, another AI algorithm employs the communication between the PDs in the same line. Then, as alternative protection to provide the protection system with another level of security in case of communication issues or cyberattacks, a third algorithm based on the local data of each PDs is proposed. Both simulations using MATLABTM SIMULINK and experimental results utilizing a scaled physical grid validated the protection algorithms. The scaled grid has been designed for the smart grid in order to test the behavior of the protection scheme experimentally.

Amplitude Based Pilot Protection for Transmission Line

Abstract: Distance protection and differential protection schemes are the two primary types of protection schemes employed in gearbox line protection today. However, industrial practice has shown that commonly used gap prevention techniques are limited in tripping speed and selectivity. The timing of the samples in each of the two relays located at the gearbox line terminals also affects the differential protection mechanism. On the other hand, pilot safety schemes using only the communication link to exchange local decision-making about fault conditions are not affected. These method include protection of Extra High Voltage (EHV) and Ultra High Voltage (UHV) transmission lines. Synchronization of time. The problem of creating a fast and accurate fault detection system for the safety of EHV/UHV transmission lines, which is crucial in present power systems, is the subject of this master's thesis. The protection method described in this thesis is the foundation for the detection and analysis of waves travelling wave along transmission at fault initiation. This method compares the arrival of the first traveling waves at both ends of the protected line with respect to direction. This will establish whether the fault is located in the safe zone or not. Based on high voltage transmission network safety requirements a suitable phase sequence algorithm is developed to control single phase tripping. Finally, through simulations conducted in the MATLAB environment, practical design concerns for incorporating the newly proposed protection algorithm into a numerical relay unit are investigated.

Power differential protection for half-wavelength transmission lines—Software in the loop analysis

Half-wavelength transmission line protection is a challenge that hinders the implementation of this technology. However, this line is considered an interesting alternative to transmit bulk power blocks over very long distances and to connect wind and photovoltaic generation to an electrical power system. This study introduces a method to protect a half-wavelength transmission line. The proposed complex plane-based protection algorithm uses a differential complex power in the sequence domain to detect faults along the entire line. The embedded spark-gap mitigation device is properly considered because it is a necessary apparatus to remove severe resonant fault conditions. A time-domain analysis shows that the proposed algorithm achieves robust performance for both internal and external faults.

Resource-efficient protection scheme for optical service units in fifth-generation fixed networks

One of the visions of fifth-generation fixed networks (F5G) is to provide a guaranteed reliable experience (GRE). Optical transport networks (OTNs) represent a primary candidate technology to offer high-quality bandwidth in F5G and hence to support GRE. Unfortunately, current OTN technologies provide large-bandwidth tunnels for carrying aggregated (typically, Ethernet) traffic, and corresponding protection techniques in OTNs consume a lot of resources. The emergence of a new technology called an optical service unit (OSU), which subdivides the payload block of traditional optical data units into smaller units, allows for the development of more flexible and resource-efficient protection schemes. In this paper, we propose a new resource-efficient protection scheme for OSU-based OTNs called OSU protection (OSU-P), with the aim to save network resources while providing individual customized protection for each single user. OSU-P only reserves small-bandwidth protection/backup connections for protected services; then, when a failure occurs, the protection bandwidth is adjusted to the bandwidth required by the service during the switching process. This scheme can save a significant amount of network resources, but it may encounter resource conflicts between the protected services and other preemptable services after a failure occurs. Hence, we also propose a deterministic protection algorithm and a preemptable service provisioning algorithm based on overlapping risk avoidance, which can ensure successful recovery switching of protected services and the least impact on preemptable unprotected services after a network failure occurs. Simulation results show that, compared with traditional 1+1 and 1:1 protection schemes, OSU-P can reduce spare resources allocated for protection by about 30% and 11%, respectively, and reduce the blocking rate by about 27% and 10%, respectively. The performance of the proposed algorithms in terms of the percentage of unsuccessful protection and affected preemptable services is also verified.

Исследование алгоритмов работы дистанционной защиты в системах распределенной генерации

Current trends in the development of power supply systems for industrial facilities when applying the principles of distributed generation consist in the implementation of power supply from several power sources of different types and characteristics (photovoltaic cells, wind power plants, microturbine plants, diesel power plants), the maximum approximation of power sources to electrical loads, the use of electricity storage. The availability of such installations near consumers reduces the quantitative energy consumption by reducing the technical losses of the ge¬nerated energy and reducing dependence on fossil fuels. However, with these advantages, distri¬buted generation has created technical problems, one of which is the complication of relay protection systems due to the possibility of powering the damage point from different sides. This circumstance requires the development of new algorithms and protection schemes to ensure selectivity and to increase the sensitivity of relay protection. The purpose of the study is to analyze the algorithms of remote protection in distributed generation systems. The methods used comprise an integrated approach, including scientific analysis, processing and analysis of the results of theoretical and experimental studies in the field of relay protection of electrical complexes in networks with distributed generation. The results obtained present the analysis of various algorithms for the implementation of protection, which were implemented as proposals for distribution networks. The system of remote protection in networks containing distributed generation systems is presented, and the algorithms of operation are compared to increase the sensitivity of remote protection devices to the occurrence of various emergency modes: single-phase and three-phase short circuits. Several algorithms for increasing the sensitivity of remote protection for distribution networks in the presence of several power sources are considered. The comparison of these algorithms according to the criteria of the implementation cost, the accuracy of implementation, the number of necessary input data is also carried out. Practical significance of the research the research results can be used to take into account the effect of changes in the parameters of protected connections under conditions of electrical complexes operation in a network with distributed ge¬neration on the effectiveness of remote protection. They make it possible to increase the sensitivity and selectivity of the remote protection operation in case of emergency situations.

A Layered Encryption Model PABB Based on User Privacy in E-commerce Platforms

In the era of big data, e-commerce platforms have increasingly strict requirements for encryption systems to prevent user privacy breaches. Traditional encryption systems use a single encryption algorithm, which cannot achieve a balance between efficiency and security. The layered encryption model PABB classifies and layers user data of different security levels, using targeted different encryption algorithms for protection, balancing the requirements of security and efficiency.

People Taking Photos That Faces Never Share: Privacy Protection and Fairness Enhancement from Camera to User

The soaring number of personal mobile devices and public cameras poses a threat to fundamental human rights and ethical principles. For example, the stolen of private information such as face image by malicious third parties will lead to catastrophic consequences. By manipulating appearance of face in the image, most of existing protection algorithms are effective but irreversible. Here, we propose a practical and systematic solution to invertiblely protect face information in the full-process pipeline from camera to final users. Specifically, We design a novel lightweight Flow-based Face Encryption Method (FFEM) on the local embedded system privately connected to the camera, minimizing the risk of eavesdropping during data transmission. FFEM uses a flow-based face encoder to encode each face to a Gaussian distribution and encrypts the encoded face feature by random rotating the Gaussian distribution with the rotation matrix is as the password. While encrypted latent-variable face images are sent to users through public but less reliable channels, password will be protected through more secure channels through technologies such as asymmetric encryption, blockchain, or other sophisticated security schemes. User could select to decode an image with fake faces from the encrypted image on the public channel. Only trusted users are able to recover the original face using the encrypted matrix transmitted in secure channel. More interestingly, by tuning Gaussian ball in latent space, we could control the fairness of the replaced face on attributes such as gender and race. Extensive experiments demonstrate that our solution could protect privacy and enhance fairness with minimal effect on high-level downstream task.

An Adaptive Centralized Protection and Relay Coordination Algorithm for Microgrid

To meet the increased customer demands, microgrid evolved. The structure of microgrid changes dynamically due to the intermittent nature of renewable-based generation, status of the distributed generator and opening of breakers for fault/maintenance. Hence, the magnitude of fault current is dynamic in nature. In order to deal with these dynamic changes, this paper addresses an adaptive central microgrid controller-based protection and relay coordination scheme, which revises the relay settings dynamically (both radial and looped configuration) for every change in topology. In the proposed algorithm, the primary relay responds to a fault immediately since the individual relays are given with fault level setting. For any abnormality in the network, the fault location is determined both via local relay and microgrid central controller (MCC). Hence, even though the local relay fails to identify the fault due to high fault impedance, the MCC locates the fault accurately and isolates the minimum faulty part. The coordination between relays is carried out by MCC in a time-graded manner based on microgrid central protection and relay coordination algorithm. The proposed algorithm is tested using Matlab in a microgrid built based on the IEEE 33 bus distribution network.